Automatic slack-adjuster.



R. C. SWARTZWELDER.

AUTOMATIC SLACK ADJUSTER.

Patented Oct. 3,1916.

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RICHARD G. SWARTZWELDER,'OF SWISSVALE, PENNSYLVANIA, ASSIGNOR TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA, A COB- PORATION OF PENNSYLVANIA.

Application-filed May 14, 1915.

' To all whom it may concern Be it known that I, RICHARD C. .SWARTZ- WELDER, a citizen of the United States, residing at Swissvale, in the county of Allegheny and State .of Pennsylvania, have invented new and useful Improvements in Automatic Slack-Adjusters, of which the fol lowing .is a specification.

This invention relates to'railway brakes,- and more particularly to a device for automatically taking up slack to compensate for the wear of the brake shoes and lost motion in the brake rigging.

The type of automatic slack adjuster to which my invention has special reference, employs shims or washers and means for automatically. shifting the washers into a position .where they are effective to take up the slack.

One object of my invention isto provide an improved slack adjuster of the above type which is positive in action andis not liable to getout of order.

Another object is to provide means for preventing the movement of more than one shim at atime when the adjuster operates to take up slack.

Other objects and advantages will appear in the following more detailed description of the invention.

In the accompanying drawings; Figure 1 is a central sectional view of a slack adjuster embodying my invention, on line D-D of Fig. A, showing the parts in normal position; Fig. 2 a similar view, showing the parts in the act of dropping a shim into position for taking up slack; Fig. 3 a simi v lar view, showing'the parts returned to normal position, after dropping a shim; Fig. l a transverse section on line AA of Fig. 3; Fig. 5 a similar sect-iononline B-B of Fig. 3; Fig. 6 a similar section on line C-C of Fig. 3; Fig. 7 a fragmentary-plan view of a portion of the slackadj'uster; Fig. 8 a fragmentary horizontal sectional view of the shim magazine;-and Fig. 9 a detail view of the end portion of the brake cylinder piston rod at which the shim supporting bar is attached.

According to the preferred form-of my invention, a casing 1 is applied to the brake cylinder in place of the usual brake cylinder head, with the usual brake cylinder releasespring 2 engaging alateral wall 3 of Specification of Letters Patent.

7 Patented 0a. 3, rare.

Serial No. 28,056.

the casing. Secured to the outer end of the brake cylinder piston rod 4; is asquare bar 5 adapted to engage, directly. orthrough the intermediary of one or more shims, a casting 6 to which the brake rigging is operatively connected. A rod 711's secured to the outer end of the bar 5 and extends through an aperture in the castingv 6.

A shelf 8 having extended laterally grooved portions;v is secured by bolts 9 to the casing =1 and and a shim. magazine 10 is mounted thereon, said magazine being open at the under side and having longitudinal guides 11 at the sides adapted to slide within the .grooves of the shelf 8. WVithin the magazine are mounted a plurality of shims 12, preferably having the vertical edges chamfered to fit corresponding recesses in the shim magazine, as shown in Fig. 8, so

asto maintain each shim in position, without the use of springs or other devices. The shims 12'are madeU shaped, with the'inner edges inclining outwardly, seam they may readily drop down over a flat supporting bar 13 having itsouter end secured to the casting'G, the bar 5 being grooved out to accommodate the bar 13.

For effecting the release movement of the brake rigging, the casting 6 contains a spring pressed pawl 14L adapted to engage teeth =15 in the rod 7, andsaid pawl is provided with a wedge 16 adapted, when the parts are returned to release position to engage a corresponding reverse wedge 17 carried bythe magazine 10, for the purpose of retractingthe pawl 1A and thus permitting relative movement between the casting 6 and the bar 5. g

A standard 18 is secured to the top of the magazine cage 10 and carries a rod 19 having teeth 20.: Surrounding the outer end'of the rod 19 is a casting 21 secured in a wall 28 of the casting 1 and having a chamber containing a slip clutchring, 22 adapted to assist in preventing the return movement of the rod 19.

A stationary pawl 23 is mounted in a block 24 secured between the side walls of the casing 1 and a movable pawl 25-is mount ed in a block 26 adapted to slide on bolts 27 secured in the vertical wall 28 of casing 1. A movable ring 29 is mounted on a projecting sleeve portion 30 of the block 26 and has'd'ownwardly projecting arms 31 adapting their outer ends chamfered to engage a conical projection 35 of the casting 21.

In operatlon, assuming the parts 1n normal pos1t1on, asshown 1n F 1g. 1 of the drawings, if an application of the brakes is made,

the brake cylinder piston moves out and with it the piston rod and the square bar 5. The first movement of the bar5 causes the casting 6 to move away from the magazine casing 10 and this permits the wedge 16 to slide off of the wedge 17 so that the pawl 14; will engage one of the teeth of the rod 7. If the piston travel exceeds the desired amount, the outward movement of the bar 5 will cause the fingers 32 to engage the arms 31 and further movement will result in the finger-s32 pushing the arms 31 and through engagement of the inner ends of the trip levers 3% with the ring 29, the block 26 is carried forward, causing the pawl 25 to pull the rod 19 forward. At the same time the chamfered ends of the moving trip levers 3a commence to ride up the stationary cone 35, so that the inner ends of the levers are caused to close in and the parts are so arranged that when the rod 19 has been pulled forward the amount of one tooth, the trip levers 3 1 will have been drawn in, to the position shown in Fig. 2 of the drawings, so that any further movement of the brake cylinder pistonv and the fingers 32 will merely cause the ring 29 to slide over the trip levers. This forward movement of one tooth is taken up by the stationary pawl 23, which drops into the next tooth of the rod 19, the parts now having the positions shown in Fig. 2. The teeth 20 of the rod 19 are made equal to the width of one of the shims 12, so that the forward movement a distance of one tooth causes just enough movement of the magazine casing 10 to permit the extreme forward shim 12 to drop over the edge of the shelf 8. The lower edge of the shim will now rest on top of the square portion 5 of the brake cylinder piston rod, as shown in Fig. 2 of the drawings, but cannot move to the take up position until the parts are returned to release position. The brakerigging is pulled back to release position by means of the pawl 14 engaging a tooth of the rod 7 and when the parts have moved back almost to full release position, the wedge 16 engages the wedge 17 and lifts the pawl 14 out of engagement with the teeth 15. Further release movement of the casting 6 and the brake rigging is now prevented, but the brake cylinder piston rod continues the release movement, so

that a space is left between the casting 6 and the outer end of the square bar 5 and into this space drops the shim 12, which has been resting on top of the square bar 5. The shim then rests on the supporting bar 13 in the position shown in Fig. 3 of the drawing, being interposed between the outer end of the bar 5 and the casting 6. It will now be evident that a shim 12 being positioned between the outer end of the bar 5 and the casting 6, the slack will be taken up to the extent of the width of a shim when the next application of the brakes is effected. in the release movement of the parts, as soon as the fingers 32 are drawn back out of engagement with the arms 31, the ring 29 will be moved rearwardly by the springs 33 until the same has pushed the movable block 26 up against the stationary block 2 1. This permits the pawl 25 to engage with the next inner tooth, ready for next movement to take up slack, the trip arms 3 1- by the same movement being freed from the action of the ring 29, so that they are. returned to the normal position, as shown in Fig. 1. The slip clutch ring 22 is merely employed to assist in holding the rod 19 in its adjusted position, and is not essential to the operation, although desirable. It will be evident that the same action will be caused whenever the brakes again are applied if the piston travel exceeds the predetermined amount.

Having now described my invention, what 1 claim as new and-desire to secure by Letters Patent, is

1. In a slack adjuster,v the combination with shims and means for positioning the shims to take up slack, of means for pre venting the movement of more than one shim to the adjusting position regardless of the piston travel.

'2. In a slack adjuster, the combination with shims and means for positioning the shims to take up slack, of means for limiting the adjustment to one shim at a time regardless of the piston travel.

3. In a slack adjuster, the combination with a plurality of slack adjusting shims and mechanism operating upon the brake cylinder piston travel exceeding a predetermined amount for effecting the positioning of shims to take up slack, of means adapted to limit the adjustment to a single shim.

a. A slack adjuster comprising a plurality of shims, a magazine containing said shims, a mechanism operated upon excessive brake cylinder piston travel for shifting said magazine to permit shims to drop into a slack take up position, and means for preventing movement of the magazine for more than one shim to drop.

5. A slack adjuster comprisihg a plurality of shims, a magazine containing said shims, the movement of which is adapted to permit the shims to drop into a slack take up position, a member operated upon excessive brake cylinder piston travel for moving said magazine, a trip lever, through which movement is transmitted from the brake cylinder piston to said member, and means adapted upon a predetermined movement of said member to disconnect the trip lever from engagement with said member 6. A slack adjuster comprising a plurality of shims, a magazine containing said shims, a shelf supporting the magazine, and a rod operated by excessive movement of the brake cylinder piston for shifting said magazine to permit the shims to drop over the edge of the shelf into a position for taking up slack.

7. In a slack adjuster, the combination with a plurality of shims and a rod operated by excessive movement of the brake cylinder piston for effecting the adjustment of the shims to take up slack, of trip levers through which the rod is shifted, and means operated upon a limited movement of the rod for tripping said levers, to prevent further movement of the rod.

8. In a slack adjuster, the combination with a plurality of shims and a magazine containing said shims, of a member operatively connected to the brake rigging and movable with the brake cylinder piston rod in applying the brakes, means adapted upon excessive movement of the brake cylinder piston for dropping a shim between the brake cylinder piston rod and said member, and a bar carried by said member for supporting the shim in its adjusting position.

9. In a slack adjuster, the combination with a plurality of shims and mechanism operative upon excessive movement of the brake cylinder piston for effecting the shift ing of shims to a position for taking up slack, of a ratchet bar secured to the brake cylinder piston rod, a pawl carried by the brake rigging connection for engaging the teeth of the ratchet bar to effect the release movement of the brake rigging, and means for releasing the pawl before the release .movement of the piston rod is completed to 11. In a slack adjuster, the combination with a plurality of shims for taking up slack, of a magazine containing said shims and having independent guides for each shim to thereby maintain same in position. 12. In a slack adjuster, the combination with a plurality of shims for taking up slack, of a magazine containing said shims and having vertically arranged grooves for each shim to thereby maintain said shims in position.

In testimony whereof I have hereunto set my hand.

RICHARD C. SWARTZIVELDER. Witnesses:

A. M. OLEMENTS,

S. H. KEEFER.

Copies of this patent may be obtained 1'01- five cents each, by addressing the Commissioner of Patents,

Washington, D. O. 1 r 

